#!/bin/bash

IPLIST="127.0.0.1;255.255.255.256"

ipvalid() {
      # Set up local variables
      local ip=${1:-NO_IP_PROVIDED}
      local IFS=.; local -a a=($ip)
      # Start with a regex format test
      [[ $ip =~ ^[0-9]+(\.[0-9]+){3}$ ]] || return 1
      # Test values of quads
      local quad
      for quad in {0..3}; do
        [[ "${a[$quad]}" -gt 255 ]] && return 1
      done
      return 0
    }

for i in $(echo $IPLIST | tr ";" "\n")
do
    if ipvalid "$i"; then
      echo "success ($i)"
    else
      echo "fail ($i)"
    fi
done